Sound-proofing installation system for vehicle power units

ABSTRACT

A soundproofing installation system for vehicle power units, particularly in buses with rearmounted power units, where the engine is located in a closed chamber, the chamber being in the form of a double-wall box and comprising an integral part of the vehicle structure. At least some of the confining walls of the chamber are provided with soundproofing material, and the chamber accomodates power transmission means connected to the engine, and is provided with sealed lead-throughs for systems located externally of the chamber and connected to or forming part of the power unit. The radiator system is divided into two systems, each with a separately driven fan, and is located outside the chamber.

United States Patent 1191 Gustavsson Nov. 27,1973

[5 1 SOUND-PROOF/ING INSTALLATION SYSTEM FOR VEHICLE POWER UNITS [75]Inventor: Bengt Henrik Gustavsson,

Katrineholm, Sweden 22 Filed: June 11,1971 21 Appl.No.: 152,237

[] Foreign Application Priority Data July 17, 1970 Sweden 9935/ [52] us.Cl. 180/54 A, 123/41.51, 180/68 R, 181/33 K [51] Int. Cl B60k 13/00 [58]Field of Search...., 180/54 A, 68 R, 69 R; 181/33 K, 36 D; 123/4151; /62A [5 6] References Cited UNITED STATES PATENTS 2,205,636 6/1940 Smith/54 A 1,754,257 4/1930 Britt 105/62 A 2,288,696 7/1942 Funderburk123/4129 1,997,299 4/1935 Herr 105/62 A 2,204,926 6/1940 Clingerman..180 54 A 2,253,438 8/1941 Lutz '180 68 R 2,705,540 4 1955 2161 1 180/54A 3,147,814 9 1964 Suhre. 180 54 A FOREIGN PATENTS OR APPLICATIONS761,751 6/1967 Canada.'.. 181/33 K 891,207 11 1943 France. 180/54 A1,208,482

9/1959 France 181/33 K Primary Examiner-Kenneth H. Betts AssistantExaminer-John A. Pekar Att0 rney-Cushman, Darby & Cushman 57 1 ABSTRACTA soundproofing installation systemfor vehicle power units, particularlyin buses with rearmounted power units, where the engine is located in aclosed chamber, the chamber being in the form of a double-wall box andcomprising an integral part of the vehiclestructure. At least some ofthe confining walls of the chamber are provided with soundproofingmaterial, and the chamber accomodates power transmission means con- 5Claims, 3 Drawing Figures a 1 SOUND-PROOFING INSTALLATION SYSTEM nonVEHICLE rowan UNITS The present invention relates to a sound-proofinginstallation system for vehicle power units, and is concernedmoreparticularly to such asystem in vehicles,

e.g. buses, of the type in which the vehicle power unit is mounted atthe rear of the vehicle and the engine of the vehicle is housed in aclosed chamber.

' One problem presented by buses of thetype in which the power unit ismounted in a conventional way at the i In accordance with anotherfavourable concept of can be disconnected to enable the cooling fans tobe regulated. manually. This arrangement allows the fans rear of thevehicle is the disturbing noise created, for.

example, by the enginehthepower transmission means, the cooling fans,and the resonance sound causedin the body of the vehicle by thevibration of these and other vehicle components. In addition to causingdiscomfort outside the vehicle, this noise is alsoparticularlydisturbing inside the vehicle itself, especially in thevicinity of the back seats. r

7 It is previously known, for reasons of space, to arrange the fans andradiator of the vehicle outside a closed engine chamber; see for exampleSwedish Pat. No. 147,677. The reason for this type of'installation waspromoted solely by the difficulty of finding sufficient space with moreconventional installationsystem to house larger power'units.

The object of the present invention ,is to provide a powerunitinstallation system which substantially reand is provided withsound-proofing material in at least the roof, and side walls of the boxstructure, and-which box structure accomodates power transmission meansconnected to the engine'and is provided with leadthroughs which aresealed in a known manner and which accomodate systems located externallyof the chamber and connected to or belonging to the power unit. Thus, inthis way, sound eminating from the engine and thetransmission isinsulated in the closed chamber, while the sound-proofing material inthe, de-

fining walls of the chamber renders the occurrence of resonanceoscillations in the defining walls difficult and dampens unavoidablenoise.

As with known installation systems, a part of the engine cooling system,mainlythe radiator and fanvrneans,

is located according to the system of the present invention externallyof the engine chamber. In this respect it is convenient to divide theradiator system into at least two separate radiators placedopposite eachother on generally their respective sides .of the vehicle and eachprovided with a separately driven cooking fan. By dividing the radiatorsystem in this way, the size of each fan can be made smaller than thesize of one single large fan to produce the required effect, therebyreducing the noise level from eac'hfan as a result of the subsequentreduction'of the socalled peak effect. Tests have shown that with twosmall fans, which together provide the same cooling effect as one singlefan, there "is obtained considerably less fan noise.

to be driveneither singly or together or to be temporarily disconnectedaccording to prevailing cooling requirements. Thus, in this way theenginepower is utilized to more advantage and it is possible for thedriver of the vehicle, incertain situations, to. increase or decreasethe cooling effect depending upon the conditions in which the vehicle isdriven.

According to another concept of the invention, the chamber is providedwith an air intake through which the engine actingas a suction pumpdrawsiinit's air for combustion via an air cleaner, the air ofcombustion being caused to flow around the engine before being drawninto the air cleaner. Thus, in this way'the engine chamber is wellventilated at the same time as the inflowing air is used to cool theengine bybeing brought into contact therewith. The air drawn into thechamber is thus in this way preheated. 'In accordance with yet anotheraspect ofthe inven tion, subsequent to passing the air intake, the airdrawn therethrough is passed through an intake silencing means beforeentering the engine chamber, thereby re ducing the sound level of theairentering-the chamber. The intake silencing means also prevents-soundwithin the chamber from penetrating to the surroundings.

The invention'will now be described with reference to an embodimentthereof illustrated in the accompanying drawings, in which FIG. 1 is aside view of a bus with a power unit placed at the rear thereof andinstalled in accordancewith the invention,

FIG. 2 is a rear view of the power unitinstallation'system and FIG. 3 isa plan view, partly in section, of the same installation.

Referring to FIGS. 1-3, the power unit 1 is mounted at the rear-of thevehicle with its long axis arranged transversely of the long axis of thevehicle. The power unitl is fully enclosed in a chamber 2 whose definingwalls or sides form an integral'part of the vehicle structure. The shortsides 3 and 4 of the chamber 2 form a part of respective sides of thevehicle while the rear long side 5 of the chamber is a part of the rearside of the vehicle. The three chamber sides 3, 4-and 5 are providedwith a number of access panels or the like to-en able ready access tothe chamber from without. The remaining definingsurfaces of the chamber.i.e;the front "long side 6, the roof 7 and the floor 8, may alsobeprovided with access panels or may be made fully detachable. 1

The defining walls of the chamber 2 are suitably in the form ofdouble-wall structures, partly in order to increase their rigidity andpartly to provide accomodation for sound-proofing material in at leasttheroof and the side walls of the chamber. The walls may suitably be ofsheet metal or other rigid material suitable'for use in vehicle bodiesand it is convenient to provide the inner wall facing the power unit 1with perforations. The sound-proofing filling may suitably be in theform of at least two different layers, an outer layer and an innerlayer, the outer layer being attached to'thei inside dampingcomposition, suitably asphalt or the like, or a sound dam'ping carpet ofspecific weight, while the inner layer, which is located nearest theperforations,

comprises a .sound absorbing material such as mineral wool or thelike.The outer layer'is-mainly intended to dampen vibrations andresonance oscillations, and the most effective thicknesses of the twolayers should be arrived at experimentally.

The chamber 2 also accomodatesthe power'trans-' trically andindependently of each other. Each of the radiators 12,13 is placed onits respective side of the vehicle, adjacent to or at respective sidesthereof, in a manner whereby the plane of rotation of the cooling fansis generally'parallel with the longitudinal direction of the vehicle.The fans 14,15 are mounted in vibration damping suspensions, suitably bymeans of rubber elemerits or other appropriate elements, and the size ofeach fan is smaller than-that required for only one single fan toproduce'the desired cooling effect. The two fans are both controlled bythermostats 16,17 connected with either the engine block 1 of the powerunit orthe cooling. water system c and, when necessary, can beindividually connected to or disconnected" from theirrespectivethermostats, according to cooling requirements. ltis'also'possible in accordance with the invention to disconnect thethermostatsand control the cooling fans 14,15 manually in a desiredmanner. 7

The exhaust pipe 18 of the engine passes through the front long side 6ofthe chamber and the larger portion of exhaust pipe 18 and the silencer19 are located externally of the chamber 2. Similarly to what is normalin engines fittedto watergoing craft, the exhaust pipe is provided witha water jacket, and its cooling water system is connected in parallelwith the cooling water system of. the engine block.

' Air for combustion 20 is drawn into the chamber via an air intake 21located high up on the rear, right-hand corner of the vehicle, and asuction silencer 22, which also serves to prevent sound from the chamber2 from reaching the surroundings and which opens out low down in thechamber at the same short side asthe air intake 21. The engine 1 acts asa suction pump and draws in the air sucked into the chamber via an aircleaner located high up andadjacent the other short ber are sealed inasuitable manner so as to maintain the chamber in a sealed condition andso that a minimum of noise or vibrations is or are propagated to thesurroundings or to the surrounding system.

' The engine mounting system is in the form of a threepoint mounting, anattachment 24 mounted on the 4 front long side of the engine beingsecured to the front wall of the chamber, whileeach of the two remainingattachments 25,26 is placed generally at itsrespective outer end of therear long side of the engine and see cured to the roof of the chamber.

Although the invention has been described and illustrated with referenceto a specific embodiment thereof, it willbe understood that theinvention is not restricted thereto but can be modified withinthe scopeof the accompanying claims.

What is claimed is:

1. Arrangementfor installation of an engine power I unit in a bus havinga self-supporting body comprising: a rearmounted engine laterallypositioned in the bus having a power transmission means, a coolingsystern, a'gear box, an angular transmission and output drive shaft;

a chamber including a bottom, a roof and transversely and longitudinallyextending walls, the extending walls defining confining surfaces, theconfining surfaces, the roof and bottom have double walls comprising aninner and anouter panel;

a vibration and sound-absorbing material positioned in the interspacebetween the inner and the outer panels of the roof and the confiningsurfaces; the rear transverse wall and the longitudinal walls constitutepart of the rear and rear side walls, respectively, of the bus, eachforming with their respective outer panels a part of the bus exterior;theroof, front transverse wall and the bottom united with thelongitudinalsides to rigidly form a said chamber, having the engine,gear box,angular and power transmissions and cooling system locatedinside said chamber; and at least one sound-proofed lead-throughextending through the confining surfaces to said chamber. 2. Thearrangement according to claim 1 further comprising: two separateradiators connected exteri orly of said chamber, each having aseparately driven cooling fan. g 3. An arrangement according to claim 2wherein the cooling fan is capable of being disconnected bymeans ofthermostats connected to the engine block or to the engine water coolingsystem, said thermostats also being capable of being disconnected toenable the cooling fans to be regulated manually.

4. An arrangement according to claim 1, wherein an air intake isprovided in said chamber for permitting air to travel through saidchamber to the engine, a suction silencerarranged in said chamber forcommunicating with the air intake, an air cleaner operably connected tothe engine and arranged relative thereto for accepting air from the airintake only after the air has flowed about the engine subsequent tobeing sucked into said chamber by the engine and communicating with thesuction silencer.

v5. Arrangement according to claim 1, wherein a major. portion of theengine cooling system includes a radiator and a cooling fan means thatis located externally of said chamber, characterized in that theradiator is divided into at least two separate radiators which arelocated opposite each other, generally on respective fans to beregulated manually.

1. Arrangement for installation of an engine power unit in a bus havinga self-supporting body comprising: a rearmounted engine laterallypositioned in the bus having a power transmission means, a coolingsystem, a gear box, an angular transmission and output drive shaft; achamber including a bottom, a roof and transversely and longitudinallyextending walls, the extending walls defining confining surfaces, theconfining surfaces, the roof and bottom have double walls comprising aninner and an outer panel; a vibration and sound-absorbing materialpositioned in the interspace between the inner and the outer panels ofthe roof and the confining surfaces; the rear transverse wall and thelongitudinal walls constitute part of the rear and rear side walls,respectively, of the bus, each forming with their respective outerpanels a part of the bus exterior; the roof, front transverse wall andthe bottom united with the longitudinal sides to rigidly form a saidchamber, having the engine, gear box, angular and power transmissionsand cooling system located inside said chamber; and at least onesound-proofed lead-through extending through the confining surfaces tosaid chamber.
 2. The arrangement according to claim 1 furthercomprising: two separate radiators connected exteriorly of said chamber,each having a separately driven cooling fan.
 3. An arrangement accordingto claim 2 wherein the cooling fan is capable of being disconnected bymeans of thermostats connected to the engine block or to the enginewater cooling system, said thermostats also being capable of beingdisconnected to enable the cooling fans to be regulated manually.
 4. Anarrangement according to claim 1, wherein an air intake is provided insaid chamber for permitting air to travel through said chamber to theengine, a suction silencer arranged in said chamber for communicatingwith the air intake, an air cleaner operably connected to the engine andarranged relative thereto for accepting air from the air intake onlyafter the air has flowed about the engine subsequent to being suckedinto said chamber by the engine and communicating with the suctionsilencer.
 5. Arrangement according to claim 1, wherein a major portionof the engine cooling system includes a radiator and a cooling fan meansthat is located externally of said chamber, characterized in that theradiator is divided into at least two separate radiators which arelocated opposite each other, generally on respective sides of thevehicle, each radiator is provided with a separately driven cooling fan,each cooling fan is controlled by means of thermostats connected to theengine cooling water system, and that said thermostats are capable ofbeing disconnected to enable the cooling fans to be regulated manually.